github.com/dolthub/swiss@v0.2.2-0.20240312182618-f4b2babd2bc1/fastrand.go (about)

     1  // Copyright 2023 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  //go:build !go1.22
    16  
    17  package swiss
    18  
    19  import (
    20  	_ "unsafe"
    21  )
    22  
    23  //go:linkname fastrand runtime.fastrand
    24  func fastrand() uint32
    25  
    26  // randIntN returns a random number in the interval [0, n).
    27  func randIntN(n int) uint32 {
    28  	return fastModN(fastrand(), uint32(n))
    29  }